Chitosan is a β-1,4-linked polymer of glucosamine (2-amino-2-deoxy-β-D-glucose), and is obtained by deacetylation of chitin (poly-N-acetyl glucosamine), which is abundant by-product in the crab and shrimp processing industries. Chitosan has long been indicated as exhibiting antibacterial/antioxidant action, and may be valuable resource of high utility.
The inventors of the present application have also noted the usefulness of chitosan, and previously developed a water-insoluble polymer iron chelating agent which can capture selectively biologically unstable iron (i.e., NTBI), and proposed that chelates insoluble in water are not drawn into metabolic processes in the body (see Patent Document 1).
Patent Document 1 discloses a water-insoluble polymer iron chelating agent in which a phenol based chelating agent of specific structure is bonded by chemically stable —NH—CH2— bonds to a chitosan chain, and also disclosed a method for capturing iron ions, using the polymer iron chelating agent in question.